1. Field of the Invention
The present invention relates generally to absorbent articles, such as catamenial articles, e.g. tampons, sanitary napkins, panty liners etc. and the process for their preparation. More particularly the invention relates to the combination of a hydrophobic and/or cationactive layer attached to a conventional absorbent layer, for the binding of microorganisms, specifically for treating or alleviating or prophylactically preventing fungal vaginal infections especially from Candida albicans. 
2. Description of the Prior Art
The so-called SORBACT® line of products consists of cellulose acetate fabric, cotton gauze or nonwoven (hereinafter named the SORBACT® material) treated with the fatty acid ester, for example DACC (dialkyl carbamoyl chloride) and/or AKD (alkyl ketene dimer). The treatment with fatty acid esters provides the SORBACT® material with a strong hydrophobic property. Numerous studies during the last few decades have shown that pathogenic microorganisms, such as Staphylococcus aureus, Group A streptococci and the yeast Candida albicans commonly express profound cell surface hydrophobicity. The microorganisms in the exudates from the wound needing to be treated will accompany the flow of liquid absorbed into the absorbing material and come in contact with the hydrophobic component and bind. Another antimicrobial property of the SORBACT® product is its cation activity, described in US Patent application 2006/0163149. The exterior membranes of mammalian cell exterior membranes are generally neutral. Thus the positively charged SORBACT® material preferentially binds to the negatively charged membranes of microorganisms.
The so called SORBACT®-principle discussed above is a modern and overall effective method for anti-microbial wound healing, which is described in U.S. Pat. No. 4,617,326 and U.S. Patent application 2006/0129080. Products utilizing the SORBACT® principle are commercially available. However none of the prior art describes the SORBACT® principle in combination with sanitary protection articles for protection against fungal vaginal infections.
Fungal infections and growth may occur at many places including the human body, e.g. in the vagina or in the oral cavity. Invasive fungal infections are increasing because of the growing number of immunocompromised patients (Jones, J. M. 1990. Laboratory diagnosis of invasive candidiasis. Clin Microbiol Rev 3:32-45). Many of these infections occur in critically ill patients suffering from an underlying disease. Over the past decades “Candida overgrowth” has increasingly been a problem as a result of several factors including the abundant use of antibiotics in medicine.
Candida vaginitis is an infection of the vagina. It causes a foul smelling, sticky, white-yellow discharge that may be accompanied by itching, burning and swelling. Such an infection can also make walking, urinating, or intercourse painful. Generally, the vaginal cavity exhibits an aqueous environment containing secreting glands whose fluids create an acidic pH in the range of about 4-5. In its normal state, the lining of the vagina secretes a fluid that is fermented to an acid by bacteria that are normally present. Many women harbor the yeast Candida albicans in the vagina and the peripheral areas around the vaginal opening and labia but most have no symptoms and it is harmless to them. This acidity of the vagina is a protective mechanism that helps to protect the vagina from invasion by other microorganisms.
Certain drug therapies can alter the balance of natural microorganisms that are present in the vagina, and hereby promote the growth of Candida albicans. Examples include the extended use of antibiotics, steroids and oral contraceptives with high estrogen content. Other factors that may cause Candida vaginitis include diabetes, pregnancy, using antihistamines, iron, folate, vitamin B12, or zinc deficiency. Tight fitting pants and the reactions to chemical ingredients found in soaps and detergents may also lead to Candida vaginitis.
Treatment with topical antifungal compositions, such as creams or suppositories, is normally the first choice of treatment for mild to moderate yeast infections. Serious infections, however, require a longer course of treatment. Formulation components which are released during the treatment process leak from the vagina creating unsanitary conditions and discomfort and also, more importantly, results in delivery of an unpredictable amount of the drug.
Another but not so frequent way of treating vaginal fungal infections is by using disposable articles such as tampons in order to decrease the pH. There are a number of common forms of disposable articles that are designed to absorb menstrual fluids discharged from a female's cervix, vaginal tampons, panty liners and sanitary napkins.
A wide variety of absorbent vaginal tampons has long been known in the art. Most currently commercially available tampons are made from a pledget of absorbent material comprising hydrophilic fibers such as cotton or viscose, which has been compressed into a substantially cylindrical form. Pledgets of a variety of types and constructions have been described in the art. Prior to compression, the pledget may be rolled, spirally wound, folded, or assembled as a rectangular pad of absorbent material. Tampons made from a generally rectangular pledget of absorbent material have been popular and successful in the market, for example, the tampon described in U.S. Pat. No. 4,294,253. As fluid is absorbed, these compressed tampons are expected to re-expand toward their original pre-compressed size, and to eventually become large enough to effectively cover the vaginal cavity against fluid leakage or bypass
To avoid the discomfort of inserting the tampon into the vagina due to the “dry feel”, a liquid pervious non-woven fabric cover layer is used to inhibit the shedding of fibers from the absorbent core. This is known from the disclosure of e.g. U.S. Pat. No. 4,816,100 and GB 2,010,680. This is due to the smoother nature of the non-woven fabric. Similar advantages can be obtained using plastics as cover layer material over the absorbent core of a tampon, as described in U.S. Pat. No. 5,374,258. Another method to render the tampon more comfortable is using friction-reducing agents for example: pectin hyaluronic acids, glycerides, waxes such as silicone waxes, plant waxes or paraffin as described in U.S. Patent application 2006/074391A1.
Tampons used for the treatment of fungal infections are already described in the art. U.S. Pat. No. 6,416,779, for example, describes tampons utilized for the treatment of fungal infections by intravaginal administration of therapeutic antifungal drugs to the vagina. Unlike the invention herein the tampon is just a delivery form for drugs and not a method of binding the fungi.
Another way of using sanitary articles for the treatment of fungal infections is by impregnating the tampons with pH-decreasing compounds as described in U.S. Patent application 2006/0264857 and U.S. Pat. No. 6,964,949. Further the WO application 1992/013577 discloses a tampon or sanitary napkin that is impregnated with a culture of living lactic acid producing bacteria, with the object of alleviating vaginal or urinary tract infections. The mechanism behind the antagonistic effect is not completely known but the dominating comprehension is that Lactobacillus having antagonistic properties have an ability of coaggregate with the pathogens, to produce inhibitors and to lower pH in the urogenital environment by the lactic acid production. Lactic acid bacteria require special protection during storage and therefore a more stable solution to the problem is preferable.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention, i.e. a way of combating vaginal fungal inventions utilizing the SORBACT® principle.
A typical sanitary napkin or panty liner includes a liquid pervious topsheet, a liquid impervious backsheet joined to the topsheet, and an absorbent core positioned between the topsheet and the backsheet. Nonwoven webs are often used as the topsheet because they are liquid pervious and provide a skin friendly surface. The absorbing material of the core normally comprises a hydrophilic material such as fibers. Suitable fibers include conventional hydrophilic cellulosic fibers, cotton fibers, viscose fibers or synthetic fibers, for example, polyester, polypropene or combinations thereof, and then pressed to a core.
WO2007073246 discloses an absorbent article for female use, such as a sanitary napkin preventing or reducing migration of microorganisms from the anus area to the urogenital area. This is achieved by a microorganism-hindering element or section, for preventing or reducing migration of microorganisms from the anus area to the urogenital area in the direction from the rear edge to the front edge of the article. The element or section comprises a material selected from one or more of a hydrophobic material, an antimicrobial agent and a positively charged material. The hydrophobic material can be selected from fatty acid esters but not as in the invention herein, which is from the fatty acid esters DACC and AKD, highly hydrophobic and specific for SORBACT® products. Also the microorganism-hindering section is just a limited part of the napkin in contrast to the invention herein where the whole topsheet is made of the SORBACT® material.
There are several known inventions relating to the use of antimicrobial substances and materials. One such example is found in U.S. Pat. No. 5,700,742, which relates to a method of treating a textile material to inhibit microbial growth and which comprises applying to the textile material an oligo or polymeric biguanide or salt thereof with an inorganic acid or an organic acid having a pK value above 4.5 followed by a strong organic acid having a pK value below 4.5 and free from any aliphatic or oxyalkylene chain containing 12 or more carbon atoms. A textile material treated in accordance with the claimed method is also disclosed.
U.S. Pat. No. 5,856,248 relates to cellulose fibers and products comprising cellulose fibers treated to absorb body secretions while substantially decreasing microbial growth, the fibers being chemically modified in a two-stage process comprising a first stage treatment with a water soluble salt of a transition metal and an alkali and a second stage treatment with a solution of a bisbiguanide compound, thereby forming a bond between the cellulose fibers, the transition metal and the compound. The process may utilize a rinsing step to neutral pH between the two aforementioned stages.
U.S. Pat. No. 5,817,325 relates to an article of manufacture having disposed on a surface thereof a non-leaching antimicrobial coating which kills microorganisms upon contact. The coating comprises an organic polycationic polymer matrix immobilized on the surface having bound or complexed thereto a surface-accessible antimicrobial metallic material such that the antimicrobial material does not release biocidal amounts of elutables into the surrounding environment.
Further, U.S. Pat. No. 6,160,196 relates to the same principle but adds thereto an antimicrobial active compound which is adapted to prevent infections from the outside of the pad and the antimicrobial compound is not released into the wound. U.S. Pat. No. 4,211,227 discloses a non-woven surgical sponge material comprising a layered fabric having an inner core or a substantially hydrophilic material disposed adjacent at least one outer or surface layer, or between a pair of outer layers, of a substantially hydrophobic material. The sponge material is bonded by passing the material through rolls engraved in a pattern of lands and grooves such that a repeating pattern of three degrees of compression are imposed on the material. However, the so-produced sponge does not use a hydrophobic material binding microorganisms to any great extent.
U.S. Patent Application 2006/0163149 relates to a product for absorption, whereby a hydrophobic entity and a positively charged entity are connected to a support matrix. In this method, the hydrophobic entity may be connected by using DACC, and the positively charged entity may be connected by using polyethyleneimine. Preferred fields of the application are filters, face masks, wound dressings, nasal sprays, and drapes for use during surgical intervention etc. However sanitary protection articles are not mentioned in this application nor are the treatment against fungal vaginal infections.
Even if traditional sanitary protection products solve an important problem absorbing blood, they do not have an antifungal property without additional compounds like drugs, lactic acid bacteria and pH decreasing compounds.
It is therefore a primary object of this invention to provide a device, composition and a method for prevention of fungal vaginal infections especially those caused by Candida albicans by providing an intravaginal tampon or a sanitary napkin/panty liner comprising a conventional absorbent covered with a cover layer treated according to the SORBACT® principle.